JP5128266B2 - lift device - Google Patents

Description

  The present invention relates to an elevating device that is used for cargo handling or the like by driving an elevating platform up and down.

  2. Description of the Related Art In recent years, a lifting device (loading work machine) that is mounted on a rear part of a vehicle loading platform such as a cargo vehicle and loads and unloads cargo on a loading platform by raising and lowering a lifting platform has been frequently used. In this type of lifting device, the lifting platform is moved up and down for cargo handling. When not in use (during traveling), it is common to stand the lifting platform vertically and also serve as the rear gate plate of the loading platform.

  However, in a lifting device mounted on a large vehicle, the lifting platform itself is heavy, and manual opening / closing operation (operation of standing the platform also serving as a gate plate from the horizontal to the vertical and vice versa) is impossible. Therefore, a hydraulic cylinder for opening and closing is provided separately from the hydraulic cylinder for raising and lowering driving of the raising and lowering platform.

  As a mechanism that does not use a hydraulic cylinder for opening and closing, there is Patent Document 1 by the present applicant.

In this patent document 1, an opening / closing guide rail is fixed to the vehicle chassis side, an opening / closing bar having a roller at the tip is attached to the lifting platform (gate plate) side, and the opening / closing bar is attached to the opening / closing platform. By making it rotatable in a plane parallel to the platform, it is possible to take a position where the roller at the tip of the opening / closing rod can be engaged with the guide rail and a position where the opening / closing rod is retracted inside the platform. Yes. In a state where the roller at the tip of the opening / closing rod can be engaged with the guide rail, the lifting platform can be rotated in the closing direction as the lifting platform rises.

  In the conventional example as described above, it is necessary to fix the guide rail to an appropriate position on the chassis side. However, depending on the vehicle type, an appropriate fixing position of the guide rail may not be found. In addition, the open / close bar is placed behind the platform when the lift platform is deployed horizontally, but the open / close bar on the back of the lift platform is engaged so that the roller at the tip of the open / close bar engages the guide rail. There is a problem that the operability is poor to operate the bar.

  In view of the above points, the present invention can share a hydraulic cylinder for raising and lowering and opening and closing of the raising and lowering platform, can perform switching between the raising and lowering operation and the opening and closing operation with good operability, and can simplify the mechanism. An object of the present invention is to provide an elevating device applicable to various vehicle types.

  Other objects and novel features of the present invention will be clarified in embodiments described later.

In order to achieve the above object, a first aspect of the present invention includes a guide post mounted vertically along a vehicle bed, a runner guided by the guide post so as to be movable up and down, and a closed vertical state. An elevating device comprising an elevating platform pivotally attached to the runner so as to be horizontal in an open state,
A double-acting hydraulic cylinder having one end pivotally attached to the guide post and the other end pivotally attached to an arm end fixed to the elevating platform;
A locking mechanism for locking the runner in the raised position;
The lifting platform is moved up and down by operating the double acting hydraulic cylinder in the unlocked state by the locking mechanism,
The lifting platform is opened and closed by operating the double-acting hydraulic cylinder in the runner locking state by the locking mechanism.

According to a second aspect of the present invention, a guide post mounted vertically along a vehicle bed, a runner guided by the guide post so as to be movable up and down, and horizontally when closed and opened vertically. A lifting platform pivotally attached to the runner,
A double-acting hydraulic cylinder having one end pivotally attached to the guide post and the other end pivotally attached to an arm end fixed to the elevating platform;
A locking mechanism for locking the runner in the raised position;
A descent prevention stopper provided on the elevating platform,
The lifting platform is moved up and down by operating the double acting hydraulic cylinder in the unlocked state by the locking mechanism,
By opening and closing the lifting platform by operating the double-acting hydraulic cylinder in the runner locking state by the locking mechanism,
The descent prevention stopper is in a descent prevention position engageable with the vehicle bed floor when the lift platform is closed vertically, and when the lift platform is opened horizontally, the vehicle bed floor It is characterized in that the disengagement respect.

  In the second aspect, the descent prevention stopper may be a protrusion that is fixed to the upper surface of the elevating platform and protrudes from the upper surface.

  In each aspect, the double-acting hydraulic cylinder and the locking mechanism may be provided in the guide post.

  Further, in each aspect, the locking mechanism includes a first engagement portion movably provided on the guide post side and a second engagement portion on the runner side. A configuration in which one engaging portion engages with the second engaging portion to prevent the runner from descending may be employed.

  According to the lifting device of the present invention, the hydraulic cylinder attached to the guide post can be shared for lifting and lowering and opening and closing of the lifting platform, and switching between the lifting and closing operations can be performed with good operability. As a result, it is possible to simplify the mechanism.

  In addition, a special mechanism for opening and closing is not required on the lifting platform side, and it can be applied to various vehicle types.

  Further, as in the second aspect, by providing a descent prevention stopper on the elevating platform, the descent preventing stopper can be engaged with the vehicle bed floor when the elevating platform is vertically closed. It becomes. For this reason, when the lifting platform is in a closed state, the lifting platform is unexpectedly lowered and opened even if the locking mechanism of the runner pivotally attached to the lifting platform is released due to an erroneous operation by the operator. Can be prevented in advance. Thereby, safety can be improved.

  Hereinafter, as the best mode for carrying out the present invention, an embodiment of a lifting device will be described with reference to the drawings.

  1 to 4 show an embodiment of a lifting device according to the present invention. In these drawings, guide posts 2 are attached vertically along the left and right sides of the rear part of the vehicle carrier 1, and guide rails 3 are fixed in the respective guide posts 2. Rollers 5 are pivotally attached to the runner 4 at least in two upper and lower positions (rotatably mounted), and these rollers 5 are guided by a guide rail 3 so as to be movable in the vertical direction. That is, the runner 4 with a roller provided in each guide post 2 is guided by the guide posts 2 so as to be movable up and down.

  A mounting bracket 6 is fixedly integrated with each runner 4, and the base end portion of the lifting platform 10 is provided on both the left and right sides with a bracket 6 extending outside the guide post 2 and a mounting pin 12 penetrating the platform base end portion. It is pivotally attached to the runner 4 side. As a result, the platform 10 is supported so as to be rotatable between a state where the platform 10 is expanded and opened (supported horizontally by a stopper on the bracket 6 side) and a state where it is closed vertically, and the runner 4 is driven up and down. As it is done, it can move up and down.

  In addition, arms 20 are fixed to the base end portions on both the left and right sides of the lifting platform 10. The rotation fulcrum of this arm 20 is a pin 12. A double-acting hydraulic cylinder 30 is provided between the tip of the arm 20 and the guide post 2. That is, one end of the double acting hydraulic cylinder 30 disposed in the guide post 2 is pivotally attached to the inner upper portion of the guide post 2 by the pin 31, and the other end is pivotally attached to the distal end portion of the arm 20 by the pin 32.

  A locking mechanism 40 that locks the runner 4 at the ascending limit position of the lifting platform 10 where the lifting platform 10 is at the same height as the floor surface 1 a of the vehicle loading platform 1 (holds the runner 4 so as not to descend) is provided in the guide post 2. Is arranged. The locking mechanism 40 includes an engagement lever 42 as a first engagement portion pivotally attached to the guide post 2 by a pin 41, and an engagement recess 43 as a second engagement portion formed in the runner 4. And a spring (not shown) for urging the engagement lever 42 in the right rotation direction (engagement direction). In the locked state, one end (engagement end) 42a of the engagement lever 42 is engaged (fitted) with the engagement recess 43 to prevent the runner 4 from descending. Note that the shape and mounting posture of the engaging lever 42 and the shape of the engaging recess 43 are such that the runner 4 rises from the lower limit position where the elevating platform 10 is landed to the upper limit position having the same height as the floor surface 1a. It is set not to prevent the movement of the direction.

  One end of a wire 44 is connected to the other end portion 42b of the engaging lever 42, and the other end of the wire 44 is connected to an arm 46 inside the guide post interlocked with a handle 45 provided at a position with good operability outside the guide post 2. The ends are connected. The locking mechanism 40 can be unlocked by operating the handle 45 and pulling the wire 44. That is, it is possible to remove the engagement end portion 42 a of the engagement lever 42 from the engagement recess 43 by pulling the wire 44 downward. Obviously, the operation mechanism of the engagement lever 42 is not limited to a wire, and a link or the like may be used.

  On the upper surface of the elevating platform 10, a descent prevention stopper 48, which is a triangular plate-like protrusion, protrudes from the upper surface of the platform and is fixed. The descent prevention stopper 48 becomes a descent prevention position that can be engaged with the floor surface 1a of the vehicle bed 1 when the elevating platform is vertically closed as shown in FIG. 3, and when the elevating platform is opened horizontally, The engagement is released with respect to the floor surface 1a and can be lowered.

  Although not described in detail, the guide post 2 is provided with a lock mechanism 70 for holding the elevating platform 10 in a vertically upright state. For example, the lock mechanism 70 is configured to hold the platform 10 vertically by inserting a lock pin 71 into a side surface of the elevating platform 10.

  FIG. 5 shows a hydraulic circuit for driving the lifting device, an oil tank 60, a hydraulic pump 50 that sucks up the hydraulic oil in the oil tank 60 and supplies the hydraulic oil to the two double acting hydraulic cylinders 30; An electric motor 51 that drives this, a switch 52 that controls energization of the electric motor 51, and a relief valve (safety valve) that opens when the discharge side of the pump 50 exceeds a certain pressure and returns hydraulic oil into the oil tank 60 VA6, first, second and third electromagnetic switching valves VA1, VA2, VA3, float control valve (constant flow valve) VA4, tuning valve VA5, check valve (check valve) VA7, throttle valve VA8 Have. In the hydraulic circuit of FIG. 5, the first, second and third electromagnetic switching valves VA1, VA2 and VA3 are in a non-excited state.

  The raising / lowering operation and opening / closing operation of the raising / lowering platform in the raising / lowering apparatus based on Embodiment of this invention are demonstrated using the hydraulic circuit of FIG. 5 together.

  As shown in the imaginary line (A) in FIG. 1 and FIG. 3, the lock mechanism 70 is released while the lifting platform 10 is vertically closed along the guide post 2, and the retaining mechanism 40 continues to hold the runner 4. Meanwhile, the double-acting hydraulic cylinder 30 is contracted by utilizing the weight of the lifting platform 10. Thereby, the raising / lowering platform 10 expand | deploys from the closed state of the virtual line (A) of FIG. 1 to the state opened horizontally of the continuous line (B).

  In the operation of opening the lifting platform 10 from vertical to horizontal, the first electromagnetic switching valve VA1 is de-energized in the hydraulic circuit of FIG. 5, the A coil of the second electromagnetic switching valve VA2 is excited and switched to the A side, and The third electromagnetic switching valve VA3 is excited and opened. When the pressure on the high pressure side of the hydraulic circuit is applied to the check valve VA7 through a dotted path, the check valve VA7 opens, and the lifting platform 10 starts to rotate in its own weight. Along with this, the hydraulic oil that has come out from the extension drive side oil supply port of the double acting hydraulic cylinder 30 returns to the oil tank 60 through the path of the throttle valve VA8, the check valve VA7, and the second electromagnetic switching valve VA2, but is closed. Since the flow rate is throttled by the throttle valve VA8 connected in parallel to the first electromagnetic switching valve VA1 in the above state, the opening / closing platform 10 is opened slowly.

  In the initial stage of the opening operation of the lifting platform 10, the hydraulic pump 50 may be operated for a short time to ensure the opening operation of the lifting platform 10 from the vertical state.

  Here, the operation of the descent prevention stopper 48 which is a triangular plate-like protrusion will be described. As shown in the imaginary line (a) in FIG. 1 and FIGS. 3 and 4, the lock mechanism 70 is released while the lifting platform 10 is vertically closed along the guide post 2, and the runner 4 is locked by the locking mechanism 40. Consider a case in which the holding of the runner 4 by the locking mechanism 40 is canceled due to an erroneous operation by the operator, instead of performing the operation of deploying the elevating platform 10 horizontally while continuing the holding.

  At this time, if the descent prevention stopper 48 is not provided, the runner 4 is lowered toward the landing position in FIG. 2, and there is a risk that the elevating platform 10 is unexpectedly opened halfway.

  On the other hand, when there is the descent prevention stopper 48, as shown by the solid line in FIG. 3, the descent prevention stopper 48 is engaged with the floor 1a of the vehicle bed 1 when the elevating platform 10 is closed vertically. Since the lowering prevention position is possible (it can be caught on the floor surface 1a), the lowering prevention stopper 48 abuts against the floor surface 1a even if the holding of the runner 4 by the locking mechanism 40 is released. Is prevented from falling. For this reason, the state of the virtual line (A) in FIG. 1 is maintained. Thereafter, the runner 4 may be held by the locking mechanism 40 and the normal lifting platform 10 may be opened.

  After the lifting platform 10 is deployed in a state of being opened horizontally as shown by the solid line (b) in FIG. 1 (at this time, the lowering prevention stopper 48 is disengaged so as not to be caught on the floor surface 1a as shown in FIG. 3), as shown in FIG. By pulling the wire 44, the locking mechanism 40 is unlocked. That is, the engaging end 42a of the engaging lever 42 is removed from the engaging recess 43 formed in the runner 4 so that the runner 4 can freely move up and down. Then, the double-acting hydraulic cylinder 30 is extended by utilizing the dead weight of the lifting platform 10 so that the lifting platform 10 is imaginary from the rising limit position (the same height as the floor surface 1a) of the solid line (c) in FIG. Lower to the descent position (landing position) of (d).

  In the lowering operation of the lifting platform 10, in the hydraulic circuit of FIG. 5, the first electromagnetic switching valve VA1 is excited and opened, the B coil of the second electromagnetic switching valve VA2 is excited and switched to the B side, and the third The electromagnetic switching valve VA3 is excited and opened. As a result, as the lifting platform 10 is lowered by its own weight, the hydraulic oil that has come out of the compression driving side oil supply port of the double acting hydraulic cylinder 30 is supplied to the third electromagnetic switching valve VA3, the tuning valve VA5, the float control valve VA4, The oil is recirculated into the oil tank 60 through the path of the second electromagnetic switching valve VA2. At this time, since the float control valve VA4 is inserted into the hydraulic oil recirculation path, the descending speed of the elevating platform 10 is maintained almost constant regardless of the weight of the load on the elevating platform 10.

  The operation of raising the lifting platform 10 from the lowered position (landing position) of the phantom line (d) in FIG. 2 to the rising limit position (the same height as the floor surface 1a) of the solid line (c) is related to the locking mechanism 40. This is performed by contracting the double-acting hydraulic cylinder 30 in the stop release state.

  In the lifting operation of the lifting platform 10, the first electromagnetic switching valve VA1 is excited and opened by the hydraulic circuit of FIG. 5, the A coil of the second electromagnetic switching valve VA2 is excited and switched to the A side, and the third electromagnetic switching is performed. The hydraulic pump 50 is operated with the valve VA3 excited and opened. The hydraulic oil discharged from the hydraulic pump 50 is supplied to the compression drive side oil supply port through the path of the second electromagnetic switching valve VA2, the float control valve VA4, the tuning valve VA5, and the third electromagnetic switching valve VA3, and is a double-acting hydraulic cylinder. 30 is contracted. In addition, the hydraulic oil that has come out from the extension drive side oil supply port is in the oil tank 60 through the first electromagnetic switching valve VA1, the check valve VA7 (pressure is applied through the dotted line path), and the second electromagnetic switching valve VA2. Return to.

  When the lifting platform 10 is closed vertically from the horizontal state at the ascending limit position (the same height as the floor surface 1a) of the lifting platform 10, the wire 44 is returned and the runner 4 is locked by the locking mechanism 40 as shown in FIG. . That is, the engaging end 42 a of the engaging lever 42 is engaged with the engaging recess 43 formed in the runner 4 to prevent the runner 4 from descending. And the raising / lowering platform 10 can be closed perpendicularly | vertically by extending the double acting hydraulic cylinder 30. FIG.

  In the closing operation of the lifting platform 10, the first electromagnetic switching valve VA1 is de-energized in the hydraulic circuit of FIG. 5, the B coil of the second electromagnetic switching valve VA2 is excited to switch to the B side, and the third electromagnetic switching valve Energize and open VA3. Then, by operating the hydraulic pump 50, hydraulic oil is supplied to the extension drive side oil supply port through the second electromagnetic switching valve VA2, the check valve VA7, and the throttle valve VA8, and the double action hydraulic cylinder 30 is extended. At this time, since the flow rate is throttled by the throttle valve VA8 connected in parallel to the closed first electromagnetic switching valve VA1, the closing operation of the lifting platform 10 is performed slowly.

  According to this embodiment, the following effects can be obtained.

(1) The double-acting hydraulic cylinder 30 attached to the guide post 2 can be shared for the raising and lowering and opening and closing of the raising and lowering platform 10, and the runner 4 can be switched between the opening and closing operation and the raising and lowering operation by the locking mechanism 40 provided on the guide post 2. It can be executed with good operability depending on whether it is locked or unlocked.

(2) Even if the lifting platform 10 is heavy, a hydraulic cylinder dedicated to opening and closing is not necessary, and the mechanism can be simplified.

(3) By providing the elevating platform 10 with the descent prevention stopper 48, the descent prevention stopper 48 can be engaged with the floor 1a of the vehicle bed 1 when the elevating platform 10 is closed vertically. It becomes. For this reason, when the lifting platform 10 is in a closed state, even if the locking mechanism 40 of the runner 4 pivotally attached to the lifting platform 10 is unlocked by an operator's erroneous operation, the lifting platform 10 is unexpectedly moved. The operation of lowering and opening can be prevented in advance. Thereby, safety can be improved.

(4) No special mechanism for opening and closing is required on the lifting platform side, and it can be applied to various vehicle types.

(5) The double-acting hydraulic cylinder 30 and the locking mechanism 40 can be provided and stored in the guide post 2, and the movable part enters the guide post 2.

  The locking mechanism that locks the runner that moves up and down in the guide post is not limited to the shape shown in the drawing. For example, the locking mechanism includes a first engagement portion that is movably provided on the guide post side, and a second engagement portion on the runner side (for example, a convex portion or a concave portion that fits with the first engagement portion). In the locked state, the first engaging portion may engage with the second engaging portion to prevent the runner from descending.

  Although the embodiments of the present invention have been described above, it will be obvious to those skilled in the art that the present invention is not limited to these embodiments, and various modifications and changes can be made within the scope of the claims.

It is embodiment of the raising / lowering apparatus which concerns on this invention, Comprising: It is a sectional side view explaining the opening / closing operation | movement of a raising / lowering platform. It is a sectional side view explaining the raising / lowering operation | movement of a raising / lowering platform similarly. It is an enlarged side view for demonstrating the effect | action of a descent | fall prevention stopper. FIG. 3 is a rear view of the lifting device with a lifting platform vertically closed. It is a hydraulic circuit diagram for raising / lowering and opening / closing the raising / lowering platform.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Vehicle bed 1a Floor surface 2 Guide post 3 Guide rail 4 Runner 5 Roller 6 Mounting bracket 10 Lifting platform 12 Mounting pin 20 Arm 30 Double acting hydraulic cylinder 40 Locking mechanism 42 Engaging lever 43 Engaging recess 44 Wire 48 Prevention of descent Stopper 50 Hydraulic pump 60 Oil tank 70 Lock mechanism

Claims (5)

A guide post mounted vertically along the vehicle bed, a runner guided by the guide post so as to freely move up and down, and a lift that is pivotally attached to the runner so as to be horizontal when closed and opened vertically. A lifting device comprising a platform,
A double-acting hydraulic cylinder having one end pivotally attached to the guide post and the other end pivotally attached to an arm end fixed to the elevating platform;
A locking mechanism for locking the runner in the raised position;
The lifting platform is moved up and down by operating the double acting hydraulic cylinder in the unlocked state by the locking mechanism,
An elevating device that opens and closes the elevating platform by operating the double-acting hydraulic cylinder in the runner locked state by the locking mechanism. A guide post mounted vertically along the vehicle bed, a runner guided by the guide post so as to freely move up and down, and a lift that is pivotally attached to the runner so as to be horizontal when closed and opened vertically. Platform,
A double-acting hydraulic cylinder having one end pivotally attached to the guide post and the other end pivotally attached to an arm end fixed to the elevating platform;
A locking mechanism for locking the runner in the raised position;
A descent prevention stopper provided on the elevating platform,
The lifting platform is moved up and down by operating the double acting hydraulic cylinder in the unlocked state by the locking mechanism,
By opening and closing the lifting platform by operating the double-acting hydraulic cylinder in the runner locking state by the locking mechanism,
The descent prevention stopper is in a descent prevention position engageable with the vehicle bed floor when the lift platform is closed vertically, and when the lift platform is opened horizontally, the vehicle bed floor A lifting device characterized in that the engagement is released.   The lifting device according to claim 2, wherein the lowering prevention stopper is a protrusion that is fixed to the upper surface of the lifting platform and protrudes from the upper surface.   4. The lifting device according to claim 1, wherein the double-acting hydraulic cylinder and the locking mechanism are provided in the guide post.   The locking mechanism includes a first engagement portion movably provided on the guide post side and a second engagement portion on the runner side. In the locked state, the first engagement portion is The elevating device according to claim 1, 2, 3, or 4, wherein the elevating device is engaged with a second engaging portion to prevent the runner from descending.

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